The present invention is directed to grafted copolymers which contain an acrylic acid ester polymer, vinyl chloride and a copolymer containing units of ethylene, carbon monoxide and n-butyl acrylate; and to their use in preparing self-supporting films (sheets) and moulded articles.
More particularly, the present invention relates to a thermoplastic graft copolymer comprising (a) an acrylic acid ester polymer; (b) vinyl chloride; and (c) a copolymer consisting essentially, by weight, of (i) 40-80% ethylene; (ii) 3-30% carbon monoxide; and (iii) 5-60% of n-butyl acrylate; and their aforementioned use in preparing films and moulded articles.
The grafted copolymers of the present invention are useful for producing films and moulded articles demonstrating good tensile properties, hardness and tear resistance. They also possess good low temperature properties, aging, weather and oil resistance, and form smooth surfaces that can be glued and welded. Typical end-uses suitable for the grafted copolymers include automobile dashboard panels and waterproofing liners.
Graft copolymers of vinyl chloride, acrylic acid esters and ethylenevinyl acetate-carbon monoxide are known (cf. EP 0 224 913 B1; U.S. Pat. No. 4,752,639). These graft polymers have desirable performance characteristics, including good tensile strength and elongation at break. It has now been found that certain of these properties, including elongation at break and tear resistance, can be surprisingly improved by particular selection of the copolymer to be grafted with vinyl chloride and acrylic acid ester.